show/hide this revision's text 2 added 17 characters in body

It is used in homotopy theory (topological modular/automorphic forms). Class field theory is used e.g. in this article http://front.math.ucdavis.edu/math.AT/0607665 of Niko Naumann.

Also, it is a trend in algebraic geometry to reduce geometric questions to finitely generated fields, so to the realm of arithmetic geometry.

show/hide this revision's text 1 [made Community Wiki]

It is used in homotopy theory (topological modular/automorphic forms). Class field theory is used e.g. in this article http://front.math.ucdavis.edu/math.AT/0607665

Also, it is a trend in algebraic geometry to reduce geometric questions to finitely generated fields, so to the realm of arithmetic geometry.